JP2670795B2 - Distance measuring device - Google Patents

Distance measuring device

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Publication number
JP2670795B2
JP2670795B2 JP63037459A JP3745988A JP2670795B2 JP 2670795 B2 JP2670795 B2 JP 2670795B2 JP 63037459 A JP63037459 A JP 63037459A JP 3745988 A JP3745988 A JP 3745988A JP 2670795 B2 JP2670795 B2 JP 2670795B2
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Japan
Prior art keywords
signal
light
light receiving
local oscillation
receiving element
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Fee Related
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JP63037459A
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Japanese (ja)
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JPH01213592A (en
Inventor
晴夫 府川
Original Assignee
株式会社ソキア
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Description

【発明の詳細な説明】 (産業上の利用分野) 本発明は、光波を使用して測距装置に関する。Description: TECHNICAL FIELD The present invention relates to a distance measuring device using light waves.

(従来の技術) 従来の光波使用の測距装置として、パルス走行時間方
式と位相比較方式が知られている。
(Prior Art) As a conventional distance measuring device using light waves, a pulse transit time method and a phase comparison method are known.

パルス走行時間方式は、目標物に向けてパルス光を放
射し、放射後反射パルス光を受光するまでの時間を測定
し、この光の往復時間から目標物までの距離を求める方
式であり、位相比較方式は、目標物に向けて正弦波的に
輝度変調した光を放射し、放射光と反射光の位相差を測
定し、この位相差から目標物までの距離を求める方式で
ある。
The pulse transit time method is a method that emits pulsed light toward the target object, measures the time until the reflected pulsed light is received after emission, and calculates the distance to the target object from the round-trip time of this light. The comparison method is a method in which light whose intensity is modulated in a sinusoidal wave is emitted toward a target object, the phase difference between the emitted light and the reflected light is measured, and the distance to the target object is obtained from this phase difference.

第4図は位相比較方式の一例を示す。 FIG. 4 shows an example of the phase comparison method.

第4図において、aは基準信号発振器、bは信号発振
器である。信号発振器bは、基準信号発振器aの基準信
号をもとにしてPLL回路や分周回路を用いて基準信号に
対して所定の周波数fLを有する正弦波の局部発振信号
sL、これより僅かに異なる周波数fSを有する正弦波の変
調信号sS及び局部発振信号sLと変調信号sSの周波数の|f
L−fS|に等しい周波数fRを有する矩形波のリファレンス
信号sRを出力する。該変調信号sSは発光駆動部cを介し
て発光素子dに加わり、発光素子dは目標物に向けて変
調光を放出するようになっている。eは目標物からの反
射変調光を電気信号に変換する受光素子で、その出力は
増幅器gを介して混合部hに入力するようになってい
る。
In FIG. 4, a is a reference signal oscillator and b is a signal oscillator. The signal oscillator b is a sine wave local oscillation signal having a predetermined frequency f L with respect to the reference signal by using a PLL circuit or a frequency divider circuit based on the reference signal of the reference signal oscillator a.
s L , a sinusoidal modulation signal s S having a slightly different frequency f S , and the frequency | f of the frequencies of the local oscillation signal s L and the modulation signal s S.
It outputs a rectangular wave reference signal s R having a frequency f R equal to L −f S |. The modulation signal s S is applied to the light emitting element d via the light emission drive section c, and the light emitting element d emits the modulated light toward the target. Reference numeral e is a light-receiving element that converts the reflection-modulated light from the target object into an electric signal, and its output is input to the mixing section h via the amplifier g.

この混合部hは、前記局部発振信号sLと受光素子eの
出力信号s′とを混合するもので、その出力から周波
数fI=|fL−fS|=1/n fS=fR(但し、n:時間拡大比)の
測定信号sIを出力し、この測定信号sIは位相差計数部i
に入力する。該位相差計数部iは測定信号sIのリフアレ
ンス信号sRからの位相遅れと、送光光路系から測量機本
体内部の固定光路系lに切換えたときの受光素子eの出
力信号s″のレファレンス信号sRからの位相遅れを測
定する。マイクロコンピュータjは該両位相遅れの差を
求め、目標物までの距離を算出する。算出した距離は表
示器kで表示される。
The mixing section h mixes the local oscillation signal s L and the output signal s ′ S of the light receiving element e, and outputs the frequency f I = | f L −f S | = 1 / nf S = f. The measurement signal s I of R (however, n: time expansion ratio) is output, and this measurement signal s I is the phase difference counting unit i.
To enter. The phase difference counting section i detects the phase delay of the measurement signal s I from the reference signal s R, and the output signal s ″ S of the light receiving element e when the light transmission optical path system is switched to the fixed optical path system 1 inside the surveying instrument body. Of the reference signal s R from the reference signal s R. The microcomputer j obtains the difference between the two phase lags and calculates the distance to the target object.

前記受光素子eの出力信号s′は目標物までの距離
に応じた位相遅れ(時間遅れ)を有し、測定信号sIは該
出力信号s′の遅れ位相角をそのまま受けついでお
り、遅れ時間はn倍に拡大されているので、該測定信号
sIとレフアレンス信号sRとを位相比較すると、測定信号
の遅れ位相すなわち距離が精度良く測定できる。
The output signal s ′ S of the light receiving element e has a phase delay (time delay) according to the distance to the target object, and the measurement signal s I receives the delay phase angle of the output signal s ′ S as it is, Since the delay time is expanded to n times, the measurement signal
By comparing the phase of s I with the reference signal s R , the delay phase of the measurement signal, that is, the distance can be measured with high accuracy.

(発明が解決しようとする課題) 従来のパルス走行時間方式は、目標物への光がパルス
光であるため、エネルギ密度の高い光を照射できるか
ら、目標点に反射プリズム等の反射光学部材を設置しな
くても測定でき、遠距離測定が可能であるが、光を放射
した後反射光を受光するまでの時間が非常に短いため、
内挿パルスが入れにくく、どうしても測定精度が悪くな
る。
(Problems to be Solved by the Invention) In the conventional pulse transit time method, since the light to the target is pulsed light, it is possible to irradiate light having a high energy density. Therefore, a reflection optical member such as a reflection prism is provided at the target point. It is possible to measure without installing it, and it is possible to measure long distances, but the time until the reflected light is received after emitting light is very short.
It is difficult to insert the interpolating pulse, and the measurement accuracy will inevitably deteriorate.

位相比較方式は、受信信号の周波数を変更して時間拡
大を行なうことができるから、分解能が優れ、測定精度
がよくなるが、エネルギ密度の高い放射光を出すには限
界があるから、パルス走行時間方式と同様の遠距離測定
が困難である。また光のエネルギ密度がパルス走行時間
方式に比べて一般に小さいので、目標点に反射プリズム
を設置するのが一般である。
Since the phase comparison method can change the frequency of the received signal to extend the time, the resolution is excellent and the measurement accuracy is good, but the pulse transit time is limited because the emitted light with high energy density is limited. It is difficult to measure a long distance like the method. Further, since the energy density of light is generally smaller than that of the pulse transit time method, it is common to install a reflecting prism at the target point.

本発明は、従来の上記の二方式の欠点を解消し、測定
精度が高いと共に遠距離測定も可能な測距装置を得るこ
とをその目的するものである。
SUMMARY OF THE INVENTION It is an object of the present invention to overcome the drawbacks of the above-mentioned two conventional methods and to obtain a distance measuring device which has high measurement accuracy and is capable of long-distance measurement.

(課題を解決するための手段) 上記の目的を達成するために、本発明の測距装置は、
発光素子と、該発光素子から変調光を放射させるための
変調信号、該変調信号とは異なる周波数の局部発振信号
及びリファレンス信号を出力する信号発生源と、目標物
からの反射変調光を電気信号に変換する受光素子と、該
受光素子の出力信号と前記局部発振信号とから両信号の
周波数の差の周波数を有する測定信号を得る変換手段
と、該測定信号のリファレンス信号に対する時間遅れを
測定する測定手段を備え、該時間遅れから目標物までの
距離を測定するようにした測距装置において、前記信号
発生源の変調信号により前記発光素子から放射される変
調光をパルス列とし、前記変換手段は前記局部発振信号
を前記受光素子の出力信号である電気パルス列によって
サンプルホールドするサンプルホールド手段であること
を特徴とするものであり、該変換手段は、前記局部発振
信号の出力回路に接続されたサンプルホールド回路から
成り、該サンプルホールド回路のスイッチは前記受光素
子の出力信号である電気パルス列によって開閉されるよ
うにしたものでもよく、また矩形波の前記局部発振信号
及び受光素子の出力信号である電気パルス列がそれぞれ
入力信号及びクロックパルス信号として入力するフリッ
プフロップから成るものでもよい。
(Means for Solving the Problems) In order to achieve the above object, the distance measuring device of the present invention is
A light emitting element, a modulation signal for emitting modulated light from the light emitting element, a signal generation source for outputting a local oscillation signal and a reference signal of a frequency different from the modulation signal, and an electric signal for reflected modulated light from a target object. A light receiving element for converting into a light receiving element, a conversion means for obtaining a measurement signal having a frequency difference between the output signal of the light receiving element and the local oscillation signal, and measuring a time delay of the measurement signal with respect to a reference signal. In a distance measuring device comprising a measuring means for measuring the distance from the time delay to the target object, the modulated light emitted from the light emitting element by the modulated signal of the signal generating source is made into a pulse train, and the converting means is Sample holding means for sampling and holding the local oscillation signal by an electric pulse train which is an output signal of the light receiving element. The conversion means may be a sample hold circuit connected to the output circuit of the local oscillation signal, and the switch of the sample hold circuit may be opened and closed by an electric pulse train which is an output signal of the light receiving element. Alternatively, the local oscillation signal of rectangular wave and the electric pulse train which is the output signal of the light receiving element may be composed of flip-flops which are inputted as an input signal and a clock pulse signal, respectively.

(作 用) 信号発生源の変調信号をパルス列変調信号としたた
め、放射光の短時間エネルギ密度を高くすることができ
るから、従来のパルス走行時間方式と同様、遠距離測定
を行なうことができ、また近距離測定では反射プリズム
が無くても測定できる。
(Operation) Since the modulation signal of the signal source is a pulse train modulation signal, the short-time energy density of the radiated light can be increased, so that long-distance measurement can be performed as with the conventional pulse transit time method. In addition, short-distance measurement can be performed without a reflecting prism.

また局部発振信号を、受光素子から出力した該局部発
振信号より僅かに異なる周波数を有する電気パルス列に
よってサンプルホールドしたので、従来の位相比較方式
における測定信号と同等の信号に変換され、高い測定精
度が得られる。
Further, since the local oscillation signal is sampled and held by an electric pulse train having a frequency slightly different from that of the local oscillation signal output from the light receiving element, it is converted into a signal equivalent to the measurement signal in the conventional phase comparison method, and high measurement accuracy is obtained. can get.

(実施例) 以下本発明の実施例を図面につき説明する。Embodiment An embodiment of the present invention will be described below with reference to the drawings.

第1図は、本発明の測距装置の一例を示す。 FIG. 1 shows an example of the distance measuring device of the present invention.

同図において、1は基準発振器、2は信号発生器、3
は発光駆動部、4は発光素子で、該発光駆動部3は、信
号発生器2から出力する変調信号とパルス列信号とし、
これによって発光素子4が放射する変調光を光パルス列
になるようにしたものである。
In the figure, 1 is a reference oscillator, 2 is a signal generator, and 3
Is a light emission drive unit, 4 is a light emitting element, and the light emission drive unit 3 is a modulated signal and a pulse train signal output from the signal generator 2,
As a result, the modulated light emitted from the light emitting element 4 is made into an optical pulse train.

前記信号発生器2は、従来の位相比較方式と同様に、
正弦波で周波数fLの局部発振信号sL周波数fRのリファレ
ンス信号sR及び周波数fSの前記変調信号sSを出力するも
ので、各周波数fL、fR及びfSの間にはfL=fS(1±1/
n)、fR=1/n fSの関係を有する。
The signal generator 2 is similar to the conventional phase comparison method,
And it outputs the modulated signal s S of a frequency f local oscillation signal L s L frequency f reference signal R s R and the frequency f S a sine wave, during each frequency f L, f R and f S is f L = f S (1 ± 1 /
n) and f R = 1 / nf S.

局部発振信号sLの出力回路5には、アナログスイッチ
6及びホールドコンデンサ7から成るサンプルホールド
回路8及び低減フィルタ9が介入接続されており、該低
減フィルタ9の出力側とリファレンス信号sRの出力回路
10はそれぞれ位相差計数部11に接続されている。該アナ
ログスイッチ6は、コンパレータ12及びビデオアンプ13
を介して受光素子14に接続され、受光素子14から出力し
た受光パルス列信号によって開閉されるようになってい
る。
A sample hold circuit 8 including an analog switch 6 and a hold capacitor 7 and a reduction filter 9 are interveningly connected to the output circuit 5 of the local oscillation signal s L. The output side of the reduction filter 9 and the output of the reference signal s R circuit
Each of 10 is connected to the phase difference counting section 11. The analog switch 6 includes a comparator 12 and a video amplifier 13
It is connected to the light receiving element 14 via the, and is opened and closed by the light receiving pulse train signal output from the light receiving element 14.

該コンパレータ12はノイズ成分をカットするものであ
り、コンピュータ15及び表示器16は従来のものと同じで
ある。
The comparator 12 cuts noise components, and the computer 15 and the display 16 are the same as those of the conventional one.

第2図(A)に示す受光パルス列信号でアナログスイ
ッチ6を開閉すると、第2図(C)に示す局部発振信号
(便宜上鋸歯形波で示す)の黒丸で示す大きさの電圧が
ホールドコンデンサ7を充電するから、サンプルホール
ド回路8から、第2図(D)に実線で示す階段状の信号
が出力する。第2図(A)よりTS/n+1(TS:周期)だ
け時間差を有する第2図(B)に示す受光パルス列信号
でアナログスイッチ6を開閉すると、第2図(C)に示
す局部発振信号の白丸で示す大きさの電圧がホールドコ
ンデンサ7を充電するから、サンプルホールド回路8か
ら第2図(D)に破線で示す段階状の信号が出力する。
この両段階状の信号の時間差はTL=n/n+1 TSであって
受光パルス列信号の時間差TS/n+1のn倍に拡大され
る。
When the analog switch 6 is opened / closed by the light receiving pulse train signal shown in FIG. 2 (A), the voltage of the magnitude indicated by the black circle of the local oscillation signal (shown as a sawtooth wave for convenience) shown in FIG. 2 (C) is held capacitor 7. , The sample-and-hold circuit 8 outputs a stepped signal shown by a solid line in FIG. 2 (D). When the analog switch 6 is opened / closed by the light receiving pulse train signal shown in FIG. 2 (B) having a time difference of T S / n + 1 (T S : period) from FIG. 2 (A), the local oscillation shown in FIG. 2 (C) is generated. Since the voltage having the magnitude indicated by the white circle in the signal charges the hold capacitor 7, the sample-and-hold circuit 8 outputs a stepwise signal indicated by a broken line in FIG.
The time difference between the two stepwise signals is T L = n / n + 1T S , which is enlarged to n times the time difference T S / n + 1 of the light receiving pulse train signals.

第1図示のサンプルホールド回路8は第3図示のよう
に、D型フリップフロップ17に置きかえることができ
る。すなわち、D型フリップフロップ17のD入力端子に
矩形波の局部発振信号を入力させ、該フリップフロップ
17のクロック端子Cに受光素子14からビデオアンプ13及
びコンパレータ12を経て受光パルス列信号を入力させて
受光パルス列信号の立上りで局部発振信号をサンプリン
グさせると、基準に対してTS/n+1だけ時間差のある受
光パルス列信号がクロック端子Cに入力したとき、Q出
力端子からn/n+1 TSの時間差がある矩形波信号を出力
する。
The sample hold circuit 8 shown in the first figure can be replaced by a D flip-flop 17 as shown in the third figure. That is, a rectangular wave local oscillation signal is input to the D input terminal of the D-type flip-flop 17,
When the light receiving pulse train signal is input from the light receiving element 14 to the clock terminal C of 17 through the video amplifier 13 and the comparator 12 and the local oscillation signal is sampled at the rising edge of the light receiving pulse train signal, a time difference of T S / n + 1 from the reference is obtained. When a certain light receiving pulse train signal is input to the clock terminal C, a rectangular wave signal having a time difference of n / n + 1 T S is output from the Q output terminal.

(発明の効果) 本発明は、上述のように構成されているので、測距精
度が高いと共に遠距離測定が可能であるという効果を有
する。
(Advantages of the Invention) Since the present invention is configured as described above, it has the advantages that the distance measurement accuracy is high and long-distance measurement is possible.

【図面の簡単な説明】[Brief description of the drawings]

第1図は本発明測距装置の回路のブロック図、第2図
(A)〜(D)はその作動説明図、第3図は本発明測距
装置の他例の回路のブロック図、第4図は従来の測距装
置の回路のブロック図である。 2……信号発生器 4……発光素子 8……サンプルホールド回路 11……位相差計数回路 14……受光素子 15……マイクロコンピュータ 16……表示器
FIG. 1 is a block diagram of a circuit of the distance measuring device of the present invention, FIGS. 2 (A) to (D) are explanatory diagrams of its operation, and FIG. 3 is a block diagram of a circuit of another example of the distance measuring device of the present invention. FIG. 4 is a block diagram of a circuit of a conventional distance measuring device. 2 …… Signal generator 4 …… Light emitting element 8 …… Sample hold circuit 11 …… Phase difference counting circuit 14 …… Light receiving element 15 …… Microcomputer 16 …… Display

Claims (3)

(57)【特許請求の範囲】(57) [Claims] 【請求項1】発光素子と、該発光素子から変調光を放射
させるための変調信号、該変調信号とは異なる周波数の
局部発振信号及びリファレンス信号を出力する信号発生
源と、目標物からの反射変調光を電気信号に変換する受
光素子と、該受光素子の出力信号と前記局部発振信号と
から両信号の周波数の差の周波数を有する測定信号を得
る変換手段と、該測定信号のリファレンス信号に対する
時間遅れを測定する測定手段を備え、該時間遅れから目
標物までの距離を測定するようにした測距装置におい
て、前記信号発生源の変調信号により前記発光素子から
放射される変調光を光パルス列とし、前記変換手段は前
記局部発振信号を前記受光素子の出力信号である電気パ
ルス列によってサンプルホールドするサンプルホールド
手段であることを特徴とする測距装置。
1. A light emitting element, a modulation signal for emitting modulated light from the light emitting element, a signal generation source for outputting a local oscillation signal and a reference signal of a frequency different from the modulation signal, and reflection from a target object. A light receiving element for converting the modulated light into an electric signal, a converting means for obtaining a measurement signal having a frequency difference between the output signal of the light receiving element and the local oscillation signal, and a reference signal of the measurement signal In a distance measuring device having a measuring unit for measuring a time delay and measuring a distance from the time delay to a target, a modulated light emitted from the light emitting element by a modulation signal of the signal generation source is converted into an optical pulse train. The conversion means is a sample and hold means for sampling and holding the local oscillation signal by an electric pulse train which is an output signal of the light receiving element. And the distance measuring device.
【請求項2】前記変換手段は、前記局部発振信号の出力
回路に接続されたサンプルホールド回路から成り、該サ
ンプルホールド回路のスイッチは前記受光素子の出力信
号である電気パルス列によって開閉されるようにしたこ
とを特徴とする特許請求の範囲第1項記載の測距装置。
2. The conversion means comprises a sample and hold circuit connected to the output circuit of the local oscillation signal, and a switch of the sample and hold circuit is opened and closed by an electric pulse train which is an output signal of the light receiving element. The distance measuring device according to claim 1, wherein
【請求項3】前記変換手段は、矩形波の前記局部発振信
号及び受光素子の出力信号である電気パルス列がそれぞ
れ入力信号及びクロックパルス信号として入力するフリ
ップフロップから成ることを特徴とする特許請求の範囲
第1項記載の測距装置。
3. The conversion means comprises a flip-flop into which the local oscillation signal having a rectangular wave and the electric pulse train which is the output signal of the light receiving element are input as an input signal and a clock pulse signal, respectively. Rangefinder according to the first section.
JP63037459A 1988-02-22 1988-02-22 Distance measuring device Expired - Fee Related JP2670795B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP63037459A JP2670795B2 (en) 1988-02-22 1988-02-22 Distance measuring device

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP63037459A JP2670795B2 (en) 1988-02-22 1988-02-22 Distance measuring device

Publications (2)

Publication Number Publication Date
JPH01213592A JPH01213592A (en) 1989-08-28
JP2670795B2 true JP2670795B2 (en) 1997-10-29

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JP63037459A Expired - Fee Related JP2670795B2 (en) 1988-02-22 1988-02-22 Distance measuring device

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Publication number Priority date Publication date Assignee Title
JP4707363B2 (en) 2004-10-20 2011-06-22 株式会社 ソキア・トプコン Light wave distance meter
JP5654253B2 (en) * 2010-03-23 2015-01-14 パナソニックIpマネジメント株式会社 Obstacle detection device

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JPH01213592A (en) 1989-08-28

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